1. Field of the Invention
The present invention relates to slime control agents especially useful in the paper and pulp industries, more particularly it relates to a slime inhibitor containing as the effective component at least one .alpha.-chloro-o-acylbenzaldoxime derivative represented by the following general formula ##STR1## wherein Y represents a halogen atom, a nitro group, a lower alkyl group, a lower alkoxyl group, a lower alkylcarboxy group, or a lower alkylamino group; R represents lower alkyl group or a halogenated alkyl group; and n represents 0 or an integer of 1-3.
The invention further relates to a slime control composition containing the aforesaid .alpha.-chloro-o-acylbenzaldoxime derivative and a known slime control agent such as a halogenated phenol or methylene bisthiocyanate as effective components, and also relates to a method of controlling slime using all such compositions.
2. Description of the Prior Art
In paper manufacturing, microorganisms are apt to generate quite easily in various processing streams. In such a case it sometimes happens that the microorganisms and the secretions thereof form a viscous material called slime on chests, pipes, and the like during the manufacture of paper. The generation of such slime is accompanied by a reduction in working efficiency, tearing of paper and the formation of stains in products, and thus causes a great amount of trouble in the production of paper and pulp. Therefore, the occurence of slime must be prevented in the manufacture of paper and pulp and it is necessary to kill the slime-forming microorganisms and to restrain the generation of such microorganisms during the manufacture of paper or pulp.
As is well known to those skilled in the art, the slime produced in the paper mill is a viscous mass having various forms and appearances such as a soft paste-like, gelatinous, gummy, fibrous, hard or horny mass which emits unpleasant odors. In many cases, the slime is a colored amorphous mass and is generally composed of heterogeneous materials, i.e., microorganisms, such as bacteria, fungi, yeast and alone and the metabolites thereof, pulp fibers and various additives incorporated into the pulp stream. The problems caused by slime are usually due to a mass as described above and are not serious if the heterogeneous materials are present in the discrete state even though the materials are contained in a relatively large amount in the pulp. A mass of slime is considered to be formed by growing viscous masses as nuclei produced by pulp fibers, additives, microorganisms and the like where the inner wall of paper mill system is rough and where the flow stream of the pulp or pulp suspension stagnates. The microorganisms, main source of the slime, are usually borne by industrial water consumed in a large quantity and raw pulp woods into paper processing systems. Additionally, since most paper processing steps are conducted while being exposed to air, there is the possibility that the pulp will be contaminated with various microorganisms floating in the air. Once the pulp is contaminated with the microorganisms, they usually grow abundantly in the raw pulp since the raw pulp and the white liquor can offer optimum conditions for microorganism growth in view of their nutrients, moisture, temperature, pH and oxygen supply. The slime formed in the paper mill systems causes various colored spots or stains in the paper product and may be the main factor in a decrease in strength and an increase in breaking of the paper product.
The slime also causes contamination and/or clogging of wires and felts used in paper processing and adversely affects the durability of such equipment due to deterioration of the material of the equipment. Thus, the operation of pulp and paper processings must be discontinued for cleaning, thereby decreasing the production efficiency and causing damage to the raw pulp materials.
It is advantageous to control or kill microorganisms having a tendency to produce such slime by a chemical treatment, i.e., by incorporating various slime controlling agents into the process streams. Slime is generally produced by various microorganisms such as bacteria, fungi, yeast and the like, so it is usually necessary to use different types of slime controlling agents at the same time. In light of the above, it would be a great advantage in the art if various microorganisms grown in the process streams in a paper mill could be controlled by a single chemical agent.
The slime controlling agents which have conventionally been used are organometallic compounds, chlorinated phenols and dithiocarbamate derivatives. These well known compounds are not satisfactory because they are toxic to humans, emit an unpleasant odor per se or even in the paper products, lower the whiteness of the paper, decrease the sizing efficiency, etc.